1. Field of the Invention
The present invention relates to slide fasteners and to a method and apparatus for making the same, and, more particularly, to the construction of chain for such slide fasteners.
2. Description of the Prior Art
Conventional slide fastener devices have long been encumbered with the problems of wear caused by abrasion between the slider and carrier tapes, of binding between the slider and interlocking elements, and of lateral stress on the chain caused by the wearer of a garment in which the slide fastener device is installed.
U.S. Pat. No. 1,947,508 is representative of the prior art in illustrating a fabric for the tapes of a slide fastener woven to present a flexible cord of reduced cross section between the bead and the flat section of the tape; however, reduction of such cord thickness is accomplished by variations in the particular weave of the fabric, which still permits fiber slippage when the fabric threads are laterally stressed.
None of the prior art devices contain any recognition and/or solution of the condition known as fiber slippage which occurs when tensile loading is applied to the textile matrix of the slide fastener chain. This condition causes stretching and separation of the threads forming the fabric of the chain tapes and results in faulty operation of the slide fastener as well as a reduction of the normal life of the slide fastener.